Protection of electrical systems from lightning and other static disturbances.



No. 852.026. PATENTED APR. 30, 1907.

R. D. MBRS-HON.

PROTECTION OF ELECTRICAL SYSTEMS FROM LIGHTNING AND OTHER STATIC DISTURBANGES.

APPLICATION FILED MAY 8. 1905.

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RALPH D. MERSHON, OF NEW YORK, N. Y. PROTECTION OF ELECTRICAL SYSTEMS FROM LIGHTNING AND OTHER STATIC DISTURBANCES.

Specification of Letters Patent.

Patented April 30, 1907.

Application filed May 8, 1905. Serial No. 259,329.

To all whom it may concern.-

Be it known that I, RALPH D. MER srroN, a

provements in Protection of Electrical Systems from Lightning and other Static Disturbances, of which the following is a specification, reference being had to the drawings accompanying and forming part of the same.

My invention relates to means for protecting "electrical systems from the destructive effects of li htning and other static disturbances, and has for its chief object to insure certainty of operation in' the devices provided to lead the static discharge to ground.

My invention contemplates the employment of any suitable arrester, that is, any suitable device or devices containing one or more dielectric gaps across which the static discharge jumps in its path to ground, and relates more particularly to the construction or arrangement, or both, of the external circuit, or that part of the external circuit, -to which the arrester devices are connected.

The main object of my invention is effected by such construction or arrangement of the external circuit as will, at the point where the arrester is connected thereto, lessen the electro-static capacity of the conductors. This may be secured by diminishing the size of the conductor or conductors in which suchresult isdesired, or by elevating the conductor or conductors for more or less of their length between the arrester and the apparatus to be rotected, whereby the capacity to ground'is essened; or by separating the conductors, whereby their capacity relative to each other is lessened. A potential wave traveling alon the conductor will, upon reaching the smal er portion of the same, have its potential increased and hence will be more certain to discharge across the gap or gaps provided for that purpose. This result willbe aided by elevating the conductors as described, so that they have a greater capacity to ground at the arrester than beyond it, Separating the conductors, to decrease the electro-stati'c capacity between them, is effective only as regards static disturbances, which tend to di'schar e from one conductor to another.

Anot ier effect of diminishing the size of the conductors as described, is to increase their inductance, so that the conductoris, in a measure, choked between the arrester and the apparatus to be protected, thus putting greater pressure on the arrester and making adischarge across the gap or-gaps still more certain.

Referring now to the drawing for a descri tion of a more convenient embodiment of t e inventionzFigure 1 is a diagram showing a system in which the conductors of the external circuit are reduced in size between the arresters and the apparatus to be protected. Fig. 2 is a diagram showing the conductors both reduced in size and elevated. Fig. 3 is a diagram showing the conductors reduced in size, elevated andseparated. Fig. 4 is a diagram showing a system inwhich the line conductors are reduced in size at the arrester and of normalsize beyond. Fig. 5 is, a diagram of a system in which the conductors are reduced, elevated and separated, and also showing the preferred manner of connecting the arresters to the conductors.

Referring now more particularly to Fig. 1: l, 2, indicate the line conductors of the external circuit, and.3 designates the apparatus to be protected from lightning pr other static disturbance. At the point where the arrester devices, illustrated diagrammatically at 4, 5, are to be connected, the conductors are reduced in size, thereby decreasing their capacity and increasing their inductance.

The result is that the electro-static wave 011 reaching the arrester will haveits potential raised, causing it to more readily break down the air-gaps and pass thence to ground in-, stead of traversing the reduced part of the conductors on to the apparatus.

In Fig. 2, the aerial conductors 6, 7, are not only reduced at the arrester, but are also elevated beyond the apparatus, thereby reducing the capacity of the conductor to ground, between the arrester and the apparatus, so that the static wave will tend still more to seek the shorter path to ground through the arr-ester. it will'of course be clear that the plan of elevating the conductors may be employed without also reducing their size,that is, the parts of the conductors which are elevated may be of normal size, Fig. 2 showing merely that the two features may be combined. Likewise, the greater elevation of the conductor or conductors may extend for only a comparatively short distance, being then brought therewith constitutin a circuit, said conductors for a portion of t eir extent being separated more than their normal distance apart,

"and one or more of the conductors being reduced in size at said separated portion of the circuit; and one or more arrester devices connected to one or more of the conductors and to ground; the se arated portion of the circuit being locate between the arrester device or devices and the apparatus, as set forth.

7. The combination of electrical apparatus a plurality of aerial conductors connected therewith constituting a circuit, said conductors for a portion of their extent being separated more than their normal distance a art and elevated above the ground more t an their normal distance therefrom; and one or more arrester devices connected to one or more of the conductors and to ground; the said separated and elevated portion of the circuit being located between the arrester to "round' the said se arated elevated and,

reduced part of the circuit being located be tween the arrester device or devices and the apparatus; as set forth.

RALPH D. MICRSHON.

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